Has BICEP2 lost its muscle?
Data claiming support for the inflationary theory of the Universe’s beginnings were released at a much ballyhooed press conference in March. (Cosmic inflation is the idea that the Universe expanded spectacularly right after the infinitesimal point that was the Big Bang.)
When I wrote about the announcement here at the time, I said I was surprised at the wholehearted embrace of a report that was so clearly contingent, tentative, preliminary. With few exceptions, physicists and physics groupies were dancing in the streets, paying at best parenthetical lip service to the way science has to work if it is to be truly scientific: results are supposed to be confirmed before they are accepted as Revealed Truth. Especially results as world-shaking as these.
The claims were based on observations of cosmic microwave background radiation left over from the Big Bang, observations made by the BICEP2 telescope at the South Pole. (BICEP is the muscular acronym for the Background Imaging of Cosmic Extragalactic Polarization experiment.) Well over 300 papers exploring the implications have appeared already, in just a couple of months, rushed into the arXiv e-print database.
We should know fairly soon, within the next year or two, whether what BICEP2 saw was the real thing. The first installment is expected in October, with release of data from Planck. Planck is the space observatory designed to study cosmic background radiation and operated by the European Space Agency. Last fall ESA declared “Mission accomplished!” and deactivated Planck, but analysis of its data goes on and on. Some teaser data were released May 12, which Kathryn Jepsen described at Symmetry.
Beginning last week, however, what physicist Sean Carroll called “Arrrgh Rumors” have been asking whether the BICEP2 results would come to literal dust. At his physics blog Résonaances on May 12, Adam Falkowski asked “Is BICEP wrong?” Noting that in March he had given the BICEP2 results only a 50-50 chance of being right, Falkowski reported that BICEP had wrongly interpreted data from Planck. “Once you correct for that and rescale the Planck results appropriately, some experts claim that the polarized galactic dust emission can account for most of the BICEP signal. The rumor is that the BICEP team has now admitted to the mistake.”
That rumor turned out to be wrong, or at least was roundly denied, according to Lisa Grossman in a May 13 piece at New Scientist.
On May 15, Carroll tweeted “Could the BICEP2 signal be dust, not CMB? Slides from Raphael Flauger suggesting yes” and linked to a public seminar by Princeton physicist Raphael Flauger (slides and video here.) Falkowski reported on the Flauger seminar on May 16. He acknowledged that the BICEP results might still turn out to be valid, but it was now up to the BICEP team to prove it.
Christopher Crockett also described the Flauger analysis May 21 in a fine open-access piece at Science News that explains the rumor story so far. It’s also a clear summary of what the issues are. “This is not so much a squabble, but the discovery process in action,” he concludes.
An early skeptic was cosmologist Peter Coles, who blogs at In the Dark. He, too, analyzed the rumor and its aftermath, and observed, “I’m not particularly keen on the rumour-mongering that has gone on, but then I’m not very keen either on the way the BICEP2 result has been presented in some quarters as being beyond reasonable doubt when it clearly doesn’t have that status. Yet. Rational scepticism is a very good thing. It’s one of the things that makes science what it is. But it all too easily turns into mudslinging.”
Cosmologist Sesh Nadathurm, who blogs at Blank On The Map, dismissed this week’s events as “a minor kerfuffle.” Which it is not, as I explain below. While I think Nadathurm is wrong about the importance of the flap, the post is a clear explanation of the technical issues.
Why the BICEP2 rumor-mongering is not a minor kerfuffle
Here’s why this tale is neither minor nor kerfuffle. As Joel Achenbach declared at Achenblog, “Cosmic inflation had been discussed for more than three decades, but this would be the first strong evidence for it.” Michael Lemonick points out in a May 21 SciAm post, “the BICEP2 results are crucial to verifying inflation, a cornerstone of modern cosmology.”
The rumor about BICEP2 results may have been denied, but it has prompted several physicists to go public with objections they say they have harbored since the findings were released in March. Lemonick rounds up some of these objections and says several physicists have not been able to replicate the BICEP2 calculations. (A BICEP2 paper was posted publicly in March but has not yet been published in a peer-reviewed journal, nor have the original data been released.)
Flauger told Ron Cowen at Nature News that he still hopes a signal will be confirmed. “I’m not trying to pick a fight; this is how science works, that someone presents a result and someone else checks that. But it doesn’t usually happen in public like this.”
Young blood reverses aging
How the Universe began is arguably the most important story ever, but for nearly everyone except people who work in astrophysics and those of us who write about it, probably some religious folks too, it’s a topic with no impact on daily life.
This week, however, came science news of interest to pretty much everyone: experiments showing that there’s something in our blood that can reverse aging. Well, not our blood. Mouse blood. But the assumption is that if mice have it, we probably do too. And you can bet the pharmas are trying to concoct a patentable version of whatever it is as we speak.
Looks to me as if we need to take seriously these three new papers. These studies are not quack science, and they don’t seem to have been seriously misinterpreted by journalists who failed to understand the work or are trying to grab headlines. Nor is their reception a case of BICEP-like premature enthusiasm for preliminary results. The three are in peer-reviewed journals and are reporting on the latest results from long-term projects.
GDF11: the magic bullet against aging?
Two papers in Science report on recent findings from long-running investigations of what happens when the circulatory systems of young mice and old mice are joined in a somewhat creepy process called parabiosis. Old mice seem to benefit from substances in the young blood, one of which is a protein, GDF11. Doses of the protein alone rejuvenate heart and skeletal muscle and improve brain function: in this case olfaction, a huge part of mouse life.
At Ars Technica, John Timmer says the work implies that brain aging is not intrinsic to neurons but rather is a product of interaction with the environment and therefore might be modified. I expect the line of human volunteers eager to ingest just about anything has formed already.
At In the Pipeline, Derek Lowe says, “You might need a lot of protein, though, and there’s no telling how often you’d need infusions of it, but to roll back aging people would presumably put up with quite a bit of inconvenience.” Lowe thinks it’s likely there might be molecular targets in the GDF11 pathways, which is where the pharmas come in. The speculation is that rejuvenation is due to increased proliferation of stem cells. Lowe notes that up to now GDF11 has been believed to prevent formation of new brain cells, which shows how little is known about it.
At Mindblog, Deric Bownds cautions against profligate shooting up with GDF11. He warns, “waking up too many stem cells to start multiplying might increase the incidence of cancer.”
Young blood serum infusions help the aging brain
The third paper, in Nature, ís in some ways even more intriguing because it shows beneficial brain effects on elderly mice from injections of blood serum from young mice. This, too, is likely to be put into practice with humans immediately. Indeed, the researchers have set up a company to begin clinical trials.
Lowe points out that blood plasma is infused thousands of times daily in every medical center in the country. He wonders what effect this work will have on “the current model of blood donation and banking, if it turns out that plasma from an 18-year-old is worth a great deal more than plasma from a fifty-year-old. I hope that the folks at the Red Cross are keeping up with the literature.”
National Institutes of Health Director Francis Collins proudly blogs a detailed account of all three papers. All this work, it turns out, has been funded by we ourselves, the US taxpayers. Do you suppose small-government commentators and Congresspersons will have the nerve to argue that it’s a waste of public money? Can opposing a cure for aging possibly be good politics?